[ETHER DOME, Massachusetts General Hospital, Boston, Massachusetts]

More than a century-and-a-half ago, in the operating theater on the top floor of the MGH’s Bulfinch Building, now known as the Ether Dome, one of the greatest moments in medicine occurred.

On Oct. 16, 1846, William T.G. Morton, a Boston dentist, demonstrated the use of ether during surgery, ending the indescribable pain — and the overwhelming dread — that had been associated with the surgeon’s knife.

The most recent renovation of the Ether Dome, which was designated a National Historic Site in 1965, and, with the Bulfinch Building, added to the roster of National Historic Landmarks in 1971, was accomplished by architects and designers who relied on historical documents and photos as well as clues from the current room. Early daguerreotype images of the room show that the original floor was made of wooden strips approximately five inches wide, which were replaced with concreteas part of a 1930s overhaul focused on bringing the site up to safety and fire codes. The cork floor seen in recent years has now been replaced with five-inch wide oak floor boards replicating the original pattern.

Above: Exterior view of the Bulfinch Building with its distinctive Ether Dome. Right: The historic Ether Dome, which is still used for lectures.